<x-flowed>Carl, You never cease to amaze me! I appreciate the detailed answer to a
technical question--and that in such short order. It clarifies a lot. Thanks.

The statement in MH (203) is as follows--it sounds very much like Smyth's
that you cited:

")/ESTI retains its accent at the beginning of a sentence, and when it =
~exists~ or ~is possible~; also after OUK, MH, EI, hWS, KAI, ALLA, TOUTO.
Only )~EI, among the present forms, is never enclitic."

I won't cite Robertson--as usual, he's far too wordy to be worth typing out
in an email!